Investigation of various steps involved in separation of serum proteins by paper electrophoresis and their quantitation by dyeing with bromphenol blue has revealed that the results obtained are quite dependent on a number of variables. It is essential, therefore, that rigid control of these variables be exercised and that normal values be obtained by the specific technic adopted. Normal values have been given for the technic employed and data on stability of sera at room and refrigerator temperatures have been presented.